Information signalling for network assisted interference mitigation

ABSTRACT

Methods and apparatuses for communicating in a wireless network include provision of interfering signal characteristics information to a user equipment to facilitate suppression of an interfering signal present in a downlink signal being received at the user equipment.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371of International Application No. PCT/US2013/072872, filed Dec. 3, 2013,entitled “INFORMATION SIGNALLING FOR NETWORK ASSISTED INTERFERENCEMITIGATION”, which designates the United States of America, which claimspriority to U.S. Patent Application No. 61/732,851, filed Dec. 3, 2012,entitled “ADVANCED WIRELESS COMMUNICATION SYSTEMS AND TECHNIQUES.” Theentire disclosures of which are hereby incorporated by reference intheir entireties for all purposes, except for those sections, if any,that are inconsistent with this specification.

TECHNICAL FIELD

Embodiments described herein generally relate to the field of wirelesscommunications and, more particularly, to the provision of informationto facilitate interference mitigation in a wireless network.

BACKGROUND OF THE INVENTION

It is becoming more important to be able to provide telecommunicationservices to fixed and mobile subscribers as efficiently andinexpensively as possible. Further, the increased use of mobileapplications has resulted in much focus on developing wireless systemscapable of delivering large amounts of data at high speed.

Development of more efficient and higher bandwidth wireless networks hasbecome increasingly important and addressing issues of how to maximizeefficiencies in such networks is ongoing. Many techniques for maximizingefficiencies in such networks involve increased reuse of frequencychannels and therefore co-channel interference, either from inter-cellor co-scheduled intra-cell users, is becoming a significant limitingfactor for achieving higher network capacity.

BRIEF DESCRIPTION OF THE DRAWING

Aspects, features and advantages of embodiments of the present inventionwill become apparent from the following description of embodiments inreference to the appended drawings in which like numerals denote likeelements and in which:

FIG. 1 is block diagram of an example wireless network according tovarious embodiments;

FIG. 2 is a flow diagram showing an exemplary method in an evolved nodebase station in according to various embodiments;

FIG. 3 is a flow diagram showing an exemplary method in a User Equipmentaccording to various embodiments;

FIG. 4 is a block diagram showing an example system in accordance withvarious embodiments; and

FIG. 5 is a block diagram showing an example wireless apparatusconfigured for communicating in a wireless network according to one ormore of the inventive methods disclosed herein.

DETAILED DESCRIPTION OF EMBODIMENTS

Illustrative embodiments of the present disclosure include, but are notlimited to, methods, systems, and apparatuses for selection ofacknowledgement signal timing in a wireless communication network.

Various aspects of the illustrative embodiments will be described usingterms commonly employed by those skilled in the art to convey thesubstance of their work to others skilled in the art. However, it willbe apparent to those skilled in the art that some alternate embodimentsmay be practiced using with portions of the described aspects. Forpurposes of explanation, specific numbers, materials, and configurationsare set forth in order to provide a thorough understanding of theillustrative embodiments. However, it will be apparent to one skilled inthe art that alternate embodiments may be practiced without the specificdetails. In other instances, well-known features are omitted orsimplified in order to not obscure the illustrative embodiments.

Further, various operations will be described as multiple discreteoperations, in turn, in a manner that is most helpful in understandingthe illustrative embodiments; however, the order of description shouldnot be construed as to imply that these operations are necessarily orderdependent. In particular, these operations need not be performed in theorder of presentation.

The phrase “in one embodiment” is used repeatedly. The phrase generallydoes not refer to the same embodiment; however, it may. The terms“comprising,” “having,” and “including” are synonymous, unless thecontext dictates otherwise. The phrase “A/B” means “A or B”. The phrase“A and/or B” means “(A), (B), or (A and B)”. The phrase “at least one ofA, B and C” means “(A), (B), (C), (A and B), (A and C), (B and C) or (A,B and C)”. The phrase “(A) B” means “(B) or (A B)”, that is, A isoptional.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a wide variety of alternate and/or equivalent implementations maybe substituted for the specific embodiments shown and described, withoutdeparting from the scope of the embodiments of the present disclosure.

This application is intended to cover any adaptations or variations ofthe embodiments discussed herein. Therefore, it is manifestly intendedthat the embodiments of the present disclosure be limited only by theclaims and the equivalents thereof.

As used herein, the term “module” may refer to, be part of, or includean Application Specific Integrated Circuit (ASIC), an electroniccircuit, a processor (shared, dedicated, or group) and/or memory(shared, dedicated, or group) that execute one or more software orfirmware instructions and/or programs, a combinational logic circuit,and/or other suitable components that provide the describedfunctionality.

FIG. 1 schematically illustrates a wireless communication network 100 inaccordance with various embodiments. Wireless communication network 100(hereinafter “network 100”) may be an access network of a 3rd GenerationPartnership Project (3GPP) long-term evolution (LTE) or long-termevolution-advanced (LTE-A) network such as an evolved universal mobiletelecommunication system (UMTS) terrestrial radio access network(E-UTRAN).

The network 100 may include a first base station, e.g., evolved nodebase station (eNB) 102, configured to wirelessly communicate with one ormore mobile device(s) or terminal(s), e.g., first user equipment (UE) A104 and/or second UE B 106. In various embodiments, the eNB 102 may be afixed station (e.g., a fixed node) or a mobile station/node.

Wireless communication network 100 further includes an evolved nodesecond base station (eNB) 110 covering a cell area that overlaps withthat of the first eNB 102, configured to wirelessly communicate with oneor more further mobile device(s) or terminal(s), e.g. third userequipment (UE) C 108. Thus, wireless communication network 100 can beconsidered an example of a heterogeneous network that includes cells ofdifferent sizes, each of which may re-use radio resources within thenetwork as appropriate.

In various embodiments, the UE 104-108 and/or the eNB 102, 110 mayinclude a plurality of antennas to implement amultiple-input-multiple-output (MIMO) transmission system, which mayoperate in a variety of MIMO modes, including single-user MIMO(SU-MIMO), multi-user MIMO (MU-MIMO), close loop MIMO, open loop MIMO orvariations of smart antenna processing. The UE 104-108 may provide sometype of channel state information (CSI) feedback to the eNB 102,110 viaone or more up link channels, and the eNB 102,110 may adjust one or moredown link channels based on the received CSI feedback. The feedbackaccuracy of the CSI may affect the performance of the MIMO system.

In various embodiments, the uplink channels and the downlink channelsmay be associated with one or more frequency bands, which may or may notbe shared by the uplink channels and the downlink channels. The one ormore frequency bands may be further divided into one or more subbands,which may or may not be shared by the uplink and downlink channels. Eachfrequency subband, one or more aggregated subbands, or the one or morefrequency bands for the uplink or downlink channels (wideband) may bereferred to as a frequency resource.

The base station 102 may be configured to re-use frequency resources forcommunication to both the first UE 104 and the second UE 106, forexample through use of multi-user multiple-in-multiple-out (MU-MIMO)techniques.

While embodiments are described with reference to an LTE network, someembodiments may be used with other types of wireless access networks.

The following inventive embodiments may be used in a variety ofapplications including transmitters and receivers of a radio system,although the present invention is not limited in this respect. Radiosystems specifically included within the scope of the present disclosureinclude, but are not limited to, network interface cards (NICs), networkadaptors, fixed or mobile client devices, relays, base stations,femtocells, gateways, bridges, hubs, routers, access points, or othernetwork devices. Further, the radio systems within the scope of theinvention may be implemented in cellular radiotelephone systems,satellite systems, two-way radio systems as well as computing devicesincluding such radio systems including personal computers (PCs), tabletsand related peripherals, personal digital assistants (PDAs), personalcomputing accessories, hand-held communication devices and all systemswhich may be related in nature and to which the principles of theinventive embodiments could be suitably applied.

To improve the capacity of wireless communication networks, deploymentof heterogeneous networks to achieve cell-splitting gains and MU-MIMOhave been suggested. However, in both scenarios, co-channelinterference, either from inter-cell or co-scheduled intra-cell users,is expected to become the dominant limiting factor for achieving highernetwork capacity. For example, while MU-MIMO makes use of beam steeringto limit the received signal power at the first UE 104 of the signaltransmitted to the second UE 106, the signal will still be present atthe first UE at some level. If the first and second UE are utilizing thesame frequency and time resources then the signal transmitted to thesecond UE 106 may result in co-channel interference at the first UE 104.Similarly, while the third UE 108 is communicating with second basestation 110, if the same resources are used as for communicationsbetween the first UE 104 and the first eNB 102, the signal transmittedto the third UE 108 may cause inter-cell interference at the first UE104.

In conventional systems, such co-channel or inter-cell interference ismitigated by using coordinated multi-point techniques (CoMP), whichhelps to avoid interference at the transmitting base station (i.e. onthe network side). However, interference mitigation at the UE side, byaccounting for spatial properties of the interference, can also providepromising gains in spectral efficiency.

According to some embodiments, interference mitigation at the receiverside is enhanced through the use of advanced interference cancelationalgorithms based on information provided to the UE relating to theinterference structure. For example, receivers may be provided with sideknowledge of the interfering signal, such as, but not limited to, themodulation format, the presence and characteristic of interference, itstransmission schemes including allocation, its reference symbols, andits modulation and/or coding, which are not available at the UE side ina wireless communication network. Information can be provided to thefirst UE 104 using message 112 by the first eNB 102.

According to some embodiments, the first UE 104 may receive and decodeone or more messages 114 transmitted by the second base station 110 thatprovide information on an interfering signal being transmitted from thesecond base station 110 to the third UE 108. The first UE 104 may beprovided with configuration data by the first base station 102 to allowthe first UE 104 to identify relevant information within the messages114 being transmitted by the second base station 110.

Detailed embodiments described below provide a number of ways in whichthe additional information on the structure of the interference can beconveyed to the UE 104 to assist in interference mitigation at the UE.

Referring to FIG. 2 an exemplary method 200 performed at eNB 102 of thewireless network 100 in accordance with some embodiments is shown.First, a communication channel between the first UE 104 and the eNB 102is established 202, for example using the normal UE registrationprocedure to attach to the network and request radio resources forcommunication. Once the eNB 102 has registered the presence of the firstUE 104 and allocated frequency resources for communication with thefirst UE 104, the eNB may identify 204 any other ongoing communications,for example with second UE 106, using the same frequency resources andthat may therefore cause interference at the first UE 104. If apotentially interfering signal being transmitted by the eNB 102 isidentified, then information on the interfering signal is conveyed 206to the first UE 104.

The eNB 102 may then further identify 208 signals transmitted byneighbouring eNBs, such as eNB 110, that are using the same frequencyresources. Again, if a potentially interfering signal is identified, forexample the communications between the second eNB 110 and the third UE108, then information on the interfering signal is conveyed 210 to thefirst UE 104.

According to some embodiments, the eNB 102 may only identify interferingsignals transmitted by itself (i.e. blocks 204/206) or alternativelyonly interfering signals transmitted by neighbouring eNBs (blocks208/210). Information relating to interfering signals, or interferingsignal characteristics information, may be provided as a separatemessage from the eNB 102 to the first UE 104 for each identified signal,or may be combined into a single communication for all identifiedinterference sources. In some embodiments, the information relating tointerfering signals may be provided as part of downlink controlinformation (DCI) provided to the first UE 104.

According to some embodiments, the interfering signal informationprovided by the first eNB 102 to the first UE 104 may be in the form ofparameters that identify control information being transmitted by thebase station 102, or by a neighbouring eNB 110 that contains parametersrelating to the interfering signal and that should be monitored anddecoded by the first UE 104. For example, the base station 102 couldprovide information to enable the user equipment 104 to receive anddecode downlink channel information (DCI) relating to other userequipment in the network.

FIG. 3 shows an exemplary method 300 performed at the first UE 104 inthe wireless network 100. The first UE 104 requests allocation 302 offrequency resources from the eNB 102, and receives information onallocated resources. The first UE 104 also receives 304 interferingsignal characteristics information from the first eNB 102, relating toother signals transmitted by the eNB 102 and/or neighbouring eNBs. Thereceived interfering signal characteristics information may comprise,for example, the modulation format, the presence and characteristic ofinterference, its transmission schemes including allocation, itsreference symbols, and its modulation and/or coding, of potentiallyinterfering signals.

The first UE 104 then receives 306 a downlink channel, for example thePhysical Downlink Shared Channel (PDSCH) from the eNB 102 using theprovided interfering signal characteristics information to mitigateinterference.

According to one embodiment signaling of interference information may beexplicitly included by the eNB 102 in downlink control information (DCI)sent to the UE. For example, for DCI Format 2C, which is used toschedule Physical Downlink Shared Channel (PDSCH) in Transmission Mode 9(TM9), the following information is transmitted, as defined in 3GPP TS36.211: “Evolved Universal Terrestrial Radio Access (E-UTRA); Physicalchannels and modulation”:

The following information is transmitted by means of the DCI format 2C:

-   -   Carrier indicator—0 or 3 bits. The field is present according to        the definitions in 3GPP TS 36.213: “Evolved Universal        Terrestrial Radio Access (E-UTRA); Multiplexing and channel        coding”.    -   Resource allocation header (resource allocation type 0/type 1)−1        bit as defined in section 7.1.6 of 3GPP TS 36.213        -   If downlink bandwidth is less than or equal to 10 PRBs,            there is no resource allocation header and resource            allocation type 0 is assumed.    -   Resource block assignment:        -   For resource allocation type 0 as defined in section 7.1.6.1            of 3GPP TS 36.213        -   ┌N_(RB) ^(DL)/P┐ bits provide the resource allocation        -   For resource allocation type 1 as defined in section 7.1.6.2            of 3GPP TS 36.213        -   ┌ log₂(P)┐ bits of this field are used as a header specific            to this resource allocation type to indicate the selected            resource blocks subset            -   1 bit indicates a shift of the resource allocation span            -   (┌N_(RB) ^(DL)/P┐−┌ log₂ (P)┐−1) bits provide the                resource allocation    -   where the value of P depends on the number of DL resource blocks        as indicated in section[7.1.6.1] of [3]    -   TPC command for PUCCH-2 bits as defined in section 5.1.2.1 of        3GPP TS 36.213    -   Downlink Assignment Index (this field is present in TDD for all        the uplink-downlink configurations and only applies to TDD        operation with uplink-downlink configuration 1-6. This field is        not present in FDD)—2 bits    -   HARQ process number—3 bits (FDD), 4 bits (TDD)    -   Antenna port(s), scrambling identity and number of layers—3 bits        as specified in Table 5.3.3.1.5C-1 where n_(SCID) is the        scrambling identity for antenna ports 7 and 8 defined in section        6.10.3.1 of 3GPP TS 36.212: “Evolved Universal Terrestrial Radio        Access (E-UTRA); Physical channels and modulation”.    -   SRS request—[0-1] bit. This field can only be present for TDD        and if present is defined in section 8.2 of 3GPP TS 36.213        -   In addition, for transport block 1:    -   Modulation and coding scheme—5 bits as defined in section 7.1.7        of 3GPP TS 36.213    -   New data indicator—1 bit    -   Redundancy version—2 bits        -   In addition, for transport block 2:    -   Modulation and coding scheme—5 bits as defined in section 7.1.7        of 3GPP TS 36.213    -   New data indicator—1 bit    -   Redundancy version—2 bits

In order to include additional information about one or more interferingsignals, the DCI Format may be extended or a new DCI format can bedefined. For example, in the case of one interfering signal, DCI Format2C can include additional fields as described below: To describe thepresence of interference on some physical resource blocks (PRBs) a new‘interference resource block assignment’ field can be provided to the UEin the DCI. In this case the UE can assume the presence of aninterfering PDSCH on PRBs indicated by ‘interference resource blocksassignment’ and no interference on the remaining PRBs of the UEsallocation indicated by ‘resource block assignment’ field:

-   -   Interference resource block assignment:        -   For resource allocation type 0 as defined in section 7.1.6.1            of 3GPP TS 36.213        -   ┌N_(RB) ^(DL)/P┐ bits provide the resource allocation        -   For resource allocation type 1 as defined in section 7.1.6.2            of 3GPP TS 36.213        -   ┌ log₂(P)┐ bits of this field are used as a header specific            to this resource allocation type to indicate the selected            resource blocks subset            -   1 bit indicates a shift of the resource allocation span            -   (┌N_(RB) ^(DL)/P┐−┌ log₂(P)┐−1) bits provide the                resource allocation    -   The signalling ‘interference resource block assignment’ can also        be used to indicate applicability of other parameters describing        interfering PDSCH signals to an identified set of PRBs.

To facilitate channel estimation on the indicated resource blockassignment (or over the entire resource block assignment of the UE whenthe ‘interference resource block assignment’ is not provided), theDeModulation Reference Signal (DM-RS) parameters of an interferingsignal can be provided to the UE using the following field.

-   -   Antenna port(s), scrambling identity and number of layers—3 bits        as specified in Table 5.3.3.1.5C-1 where n_(SCID) is the        scrambling identity for antenna ports 7 and 8 defined in section        6.10.3.1 of 3GPP TS 36.212

To facilitate usage of more advanced receivers that exploit thestructure of an interfering signal (e.g. the modulation of theinterfering signal for a maximum likelihood MIMO receiver or asuccessive interference cancellation receiver) information about themodulation and coding scheme can be provided to the UE using thefollowing field:

-   -   Modulation and coding scheme—5 bits as defined in section 7.1.7        of 3GPP TS 36.213

Potentially the ‘Modulation and coding scheme’ parameter can be replacedby a 2 bit parameter indicating modulation order only. For example:

-   -   00-BPSK (or 4-ASK), 01-QPSK, 10-16QAM, 11-64QAM

To facilitate use of a more advanced interference canceling receiverthat may perform joint decoding of useful and interfering PDSCH, theRadio Network Temporary Identifier (RNTI) or RNTI index (among otherconfigured RNTIs), and/or physical cell ID or index of physical cell IDs(among other configured cell IDs) may be included the DCI. The RNTI andphysical cell Id values signalled in the DCI can then be used todescramble the interfering PDSCH before joint decoding in accordance to3GPP TS 36.211, i.e.:

-   -   For each codeword q, the block of bits b^((q))(0), . . . ,        b^((q))(M_(bit) ^((q))−1), where M_(bit) ^((q)) is the number of        bits in codeword q transmitted on the physical channel in one        subframe, shall be scrambled prior to modulation, resulting in a        block of scrambled bits {tilde over (b)}^((q))(0), . . . ,        {tilde over (b)}^((q))(M_(bit) ^((q))−1) according to        {tilde over (b)} ^((q))(i)=(b ^((q))(i)+c(q)(i))mod 2    -   where the scrambling sequence c^((q))(i) is given by Section        7.2. The scrambling sequence generator shall be initialised at        the start of each subframe, where the initialisation value of        c_(int) depends on the transport channel type according to

$c_{init} = \left\{ \begin{matrix}{{n_{RNTI} \cdot 2^{14}} + {q \cdot 2^{13}} + {\left\lfloor {n_{s}/2} \right\rfloor \cdot 2^{9}} + N_{ID}^{cell}} & {{for}\mspace{14mu}{PDSCH}} \\{{\left\lfloor {n_{s}/2} \right\rfloor \cdot 2^{9}} + N_{ID}^{MBSFN}} & {{for}\mspace{14mu}{PMCH}}\end{matrix} \right.$

-   -   where n_(RNTI) corresponds to the RNTI associated with the PDSCH        transmission as described in Section 7.1[4].    -   Up to two codewords can be transmitted in one subframe, i.e.,        qϵ{0,1}. In the case of single codeword transmission, q is equal        to zero.

In the case of two or more interfering signals the multiple versions ofthe proposed fields above can be sent to the UE as a part of extended ornew DCI. While the above embodiments have been described in reference tothe particular case of Format 2C of DCI information, it will be apparentto the skilled person that the described extra fields could beincorporated into other formats described in the referenced standarddocuments. According to some embodiments, signaling of interferenceinformation may be performed implicitly by configuring the UE, viahigher layers, with one or more other users' RNTIs whose ePDCCH/PDCCHsearch space the UE may monitor in addition to its own ePDCCH/PDCCHsearch space determined by UE's own RNTI. The scrambling of ePDCCH/PDCCHDCI's CRC and scrambling of the interfering PDSCH in this case isperformed in accordance to the other users' RNTIs. In addition to otheruser RNTIs, a physical cell ID defining scrambling of the DCI may beprovided to the UE to enable neighboring cell's DCIs to be decoded bythe UE. If the DM-RS sequence, DCI scrambling, bandwidth, search space,etc associated with other UE's ePDCCH/PDCCH to be monitored by the UE isthe same as its own corresponding parameters, the UE may not need toperform blind decoding but may simply check the CRC using the C-RNTI ofthe other UE.

According to some embodiments, the UE may not need to perform multipleblind decodings to obtain the modulation and coding scheme (MCS) foranother UE if the following conditions are fulfilled.

A UE 104 may overhear PDCCH/ePDCCH for another UE 106 or 108 to obtainits modulation order (i.e. MCS). If the following conditions arefulfilled, the UE may not need to perform additional blind decoding butwill need to check the masked RNTI on the CRC to obtain the information:

-   -   The two UEs have the same search space (i.e. same hashing        function).    -   The two UEs have the same size of DCI contents (e.g. same system        bandwidth and transmission mode).    -   The two UEs are served by cells with the same physical cell ID        or configured with the same virtual cell ID.

To facilitate 1) and/or 3), the RNTI (this RNTI may be different fromthe C-RNTI) for defining a search space and/or physical/virtual cell IDfor DM-RS and DCI scrambling may be configured by radio resource control(RRC) signaling. By doing this, two PDCCH/ePDCCHs may be detectedwithout increasing the number of blind decoding attempts but by checkingtwo masked C-RNTIs (i.e. for UE 104 and for UE 106, 108). If theconfigured RNTI is applied also for the CRC mask, a one-time CRC checkcan also be performed.

As another example, if the DCI sizes are same for the two UEs (e.g. dueto the same system bandwidth and/or transmission modes), the searchspaces for the two UEs may be shared. To support this, the followingoperation may be performed:

-   -   C-RNTI-X may be configured to a UE having C-RNTI-Y to monitor        other UE's PDCCH/ePDCCH.    -   Whether or not the UE can check CRC for other UE with C-RNTI-X        may be configured by RRC signaling.    -   The UE with C-RNTI-Y may assume the same search space, same DM        RS sequence (if any), same scrambling sequence for DCI, etc.        when performing a single blind decoding with simple check of the        CRC for the other UE's C-RNTI-X.        -   The related parameters to enable a single blind decoding            attempt may be provided by RRC signaling.

According to some embodiments interference information may be signaledin additional DCI messages sent to the UE in its own ePDCCH/PDCCH searchspace, as defined by the RNTI of the UE. Since DCIs containinginformation about useful PDSCH and an interfering PDSCH are transmittedin the same ePDCCH/PDCCH search space, a special IA-RNTI (InterferenceAssistance) configured via a higher layer to the UE should be used bythe UE to descramble the DCI's CRC describing the interfering PDSCHstructure. The serving cell physical cell ID can be used by the UE fordescrambling of DCI.

According to some embodiments interference information may be signaledin DCIs sent to the UE in a special ePDCCH/PDCCH search space defined byan IA-RNTIs (Interference Assistance RNTI). In this case the searchspace may be shared by multiple UEs. To distinguish DCIs sent todifferent UEs, the scrambling of the ePDCCH/PDCCH DCI's CRC is performedby set of RNTIs configured to the UE via higher layer signaling. UE mayalso assume that RNTI used for ePDCCH/PDCCH CRC scrambling is alsoapplied to a corresponding PDSCH. In addition to the RNTI used todescramble the DCI's CRC, a physical cell ID defining scrambling of DCImay be provided to the UE to enable neighboring cells' DCI decoding bythe UE.

According to some embodiments outlined above, the search space in thePDCCH is determined in accordance to 3GPP TS 36.213 as follows:

-   -   The control region of each serving cell consists of a set of        CCEs, numbered from 0 to N_(CCE,k)−1 according to Section 6.8.1        in 3GPP TS 36.213, where N_(CCE,k) is the total number of CCEs        in the control region of subframe k. The UE shall monitor a set        of PDCCH candidates on one or more activated serving cells as        configured by higher layer signalling for control information in        every non-DRX subframe, where monitoring implies attempting to        decode each of the PDCCHs in the set according to all the        monitored DCI formats.    -   The set of PDCCH candidates to monitor are defined in terms of        search spaces, where a search space S_(k) ^((L)) at aggregation        level Lϵ{1,2,4,8} is defined by a set of PDCCH candidates. For        each serving cell on which PDCCH is monitored, the CCEs        corresponding to PDCCH candidate m of the search space S_(k)        ^((L)) are given by        L{Y _(k) +m′)mod └N _(CCE,k) /L┘}+i    -   where Y_(k) is defined below, i=0, . . . , L−1.    -   For the UE-specific search space S_(k) ^((L)) at aggregation        level L, the variable Y_(k) is defined by        Y _(k)=(A·Y _(k-1))mod D    -   where Y⁻¹=n_(RNTI)≠0, A=39827, D=65537 and k=└n_(s)/2┘, n_(s) is        the slot number within a radio frame. The RNTI value used for        n_(RNTI) is defined as described in the embodiments above.

According to some embodiments outlined above, the scrambling ofePDCCH/PDCCH DCI's CRC is determined as follows 3GPP TS 36.212:

-   -   In the case where UE transmit antenna selection is not        configured or applicable, after attachment, the CRC parity bits        are scrambled with the corresponding RNTI x_(rnti,0),        x_(rnti,1), . . . , x_(rnti,15), where x_(rnti,0) corresponds to        the MSB of the RNTI, to form the sequence of bits c₀, c₁, c₂,        c₃, . . . , c_(B-1). The relation between c_(k) and b_(k) is:        c _(k) =b _(k)    -   for k=0, 1, 2, . . . , A−1        c _(k)=(b _(k) +x _(rnti,k-A))mod 2    -   for k=A, A+1, A+2, . . . , A+15.    -   In the case where UE transmit antenna selection is configured        and applicable, after attachment, the CRC parity bits of PDCCH        with DCI format 0 are scrambled with the antenna selection mask        x_(AS,0), x_(AS,1), . . . , x_(AS,15) as indicated in Table        5.3.3.2-1 and the corresponding RNTI x_(rnti,0), x_(rnti,1), . .        . , x_(rnti,15) to form the sequence of bits c₀, c₁, c₂, c₃, . .        . , c_(B-1). The relation between c_(k) and b_(k) is:        c _(k) =b _(k)    -   for k=0, 1, 2, . . . , A−1        c _(k)=(b _(k) +x _(rnti,k-A) +x _(AS,k-A))mod 2    -   for k=A, A+1, A+2, . . . , A+15.

TABLE 5.3.3.2-1 UE transmit antenna selection mask. UE transmit antennaAntenna selection mask selection <x_(AS,0), x_(AS,1), . . . , x_(AS,15)>UE port 0 <0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0> UE port 1 <0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1>

The eNBs 102, 110 and UEs (104, 106, 108) described herein may beimplemented into a system using any suitable hardware and/or software toconfigure as desired. FIG. 4 illustrates, for one embodiment, an examplesystem 400 comprising one or more processor(s) 440, system control logic420 coupled with at least one of the processor(s) 440, system memory 410coupled with system control logic 420, non-volatile memory (NVM)/storage430 coupled with system control logic 420, and a network interface 460coupled with system control logic 420. The system control logic 420 mayalso be coupled to Input/Output devices 450.

Processor(s) 440 may include one or more single-core or multi-coreprocessors. Processor(s) 440 may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, baseband processors, etc.).Processors 440 may be operable to carry out the above described methods,using suitable instructions or programs (i.e. operate via use ofprocessor, or other logic, instructions). The instructions may be storedin system memory 410, as interference mitigation logic memory portion415, or additionally or alternatively may be stored in (NVM)/storage430, as NVM interference mitigation logic instruction portion 435.Processors(s) 440 may be configured to execute the embodiments of FIGS.2-3 in accordance with various embodiments. In an embodiment in whichthe system 400 implements eNB 102, processor(s) 440 may be configured totransmit to the UE 102 interfering signal characteristics information112.

System control logic 420 for one embodiment may include any suitableinterface controllers to provide for any suitable interface to at leastone of the processor(s) 440 and/or to any suitable device or componentin communication with system control logic 420.

System control logic 420 for one embodiment may include one or morememory controller(s) (not shown) to provide an interface to systemmemory 410. System memory 410 may be used to load and store data and/orinstructions, for example, for system 400. System memory 410 for oneembodiment may include any suitable volatile memory, such as suitabledynamic random access memory (DRAM), for example.

NVM/storage 430 may include one or more tangible, non-transitorycomputer-readable media used to store data and/or instructions, forexample. NVM/storage 430 may include any suitable non-volatile memory,such as flash memory, for example, and/or may include any suitablenon-volatile storage device(s), such as one or more hard disk drive(s)(HDD(s)), one or more compact disk (CD) drive(s), and/or one or moredigital versatile disk (DVD) drive(s), for example.

The NVM/storage 430 may include a storage resource physically part of adevice on which the system 400 is installed or it may be accessible by,but not necessarily a part of, the device. For example, the NVM/storage430 may be accessed over a network via the network interface 460.

System memory 410 and NVM/storage 430 may respectively include, inparticular, temporal and persistent copies of, for example, theinstructions memory portions holding the interference mitigation logic415 and 435, respectively. Interference mitigation logic instructionsportions 415 and 435 may include instructions that when executed by atleast one of the processor(s) 440 result in the system 400 implementinga one or both of methods 200 and/or 300, or the method(s) of any otherembodiment, as described herein. In some embodiments, instructionportions 415 and 435, or hardware, firmware, and/or software componentsthereof, may additionally/alternatively be located in the system controllogic 420, the network interface 460, and/or the processor(s) 440.

Network interface 460 may have a transceiver module 465 to provide aradio interface for system 400 to communicate over one or morenetwork(s) (e.g. wireless communication network) and/or with any othersuitable device. In various embodiments, the transceiver 465 may beintegrated with other components of system 400. For example, thetransceiver 465 may include a processor of the processor(s) 440, memoryof the system memory 410, and NVM/Storage of NVM/Storage 430. Networkinterface 460 may include any suitable hardware and/or firmware. Networkinterface 460 may be operatively coupled to a plurality of antennas toprovide a multiple input, multiple output radio interface. Networkinterface 460 for one embodiment may include, for example, a networkadapter, a wireless network adapter, a telephone modem, and/or awireless modem.

For one embodiment, at least one of the processor(s) 440 may be packagedtogether with logic for one or more controller(s) of system controllogic 420. For one embodiment, at least one of the processor(s) 440 maybe packaged together with logic for one or more controllers of systemcontrol logic 420 to form a System in Package (SiP). For one embodiment,at least one of the processor(s) 440 may be integrated on the same diewith logic for one or more controller(s) of system control logic 420.For one embodiment, at least one of the processor(s) 440 may beintegrated on the same die with logic for one or more controller(s) ofsystem control logic 420 to form a System on Chip (SoC).

In various embodiments, the I/O devices 450 may include user interfacesdesigned to enable user interaction with the system 400, peripheralcomponent interfaces designed to enable peripheral component interactionwith the system 400, and/or sensors designed to determine environmentalconditions and/or location information related to the system 400. FIG. 5shows an embodiment in which the system 400 implements a UE 104, 106,108 in the specific form of a mobile device 500.

In various embodiments, user interfaces could include, but are notlimited to, a display 540 (e.g., a liquid crystal display, a touchscreen display, etc.), a speaker 530, a microphone 590, one or morecameras 580 (e.g., a still camera and/or a video camera), a flashlight(e.g., a light emitting diode flash), and a keyboard 570.

In various embodiments, the peripheral component interfaces may include,but are not limited to, a non-volatile memory port, an audio jack, and apower supply interface.

In various embodiments, the sensors may include, but are not limited to,a gyro sensor, an accelerometer, a proximity sensor, an ambient lightsensor, and a positioning unit. The positioning unit may also be partof, or interact with, the network interface 460 to communicate withcomponents of a positioning network, e.g., a global positioning system(GPS) satellite.

In various embodiments, the system 400 may be a mobile computing devicesuch as, but not limited to, a laptop computing device, a tabletcomputing device, a netbook, a mobile phone, etc. In variousembodiments, system 400 may have more or less components, and/ordifferent architectures.

In embodiments, the implemented wireless network may be a 3rd GenerationPartnership Project's long term evolution (LTE) advanced wirelesscommunication standard, which may include, but is not limited toreleases 8, 9, 10, 11 and 12, or later, of the 3GPP's LTE-A standards.

Although certain embodiments have been illustrated and described hereinfor purposes of description, a wide variety of alternate and/orequivalent embodiments or implementations calculated to achieve the samepurposes may be substituted for the embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatembodiments described herein be limited only by the claims and theequivalents thereof.

In various embodiments, an apparatus for use in a wireless communicationsystem, the apparatus comprising a communication module configured toreceive interfering signal characteristics information, and receive adownlink signal in the presence of an interfering signal, and aninterference mitigation module coupled to the communication module andconfigured to suppress interference in the received downlink signalcaused by the interfering signal based on the interfering signalcharacteristics information.

In various embodiments, the interfering signal characteristicsinformation comprises at least one of: a modulation format, a presenceand characteristics of interference, a transmission scheme, one or morereference symbols of the interfering signal, and a modulation or codingscheme of the interfering signal.

In various embodiments, the communication module is further configuredto receive the interfering signal characteristics information from aneNodeB transmitting the downlink signal.

In various embodiments, wherein the interfering signal characteristicsinformation comprises an interference resource block assignmentcontained within a Downlink Control Information (DCI) message associatedwith the user equipment.

In various embodiments, the interference resource block assignmentindicates one or more physical resource blocks (PRBs) associated withthe interfering signal.

In various embodiments, wherein the interfering signal characteristicsinformation comprise demodulation reference signal (DM-RS) parametersassociated with the interfering signal.

In various embodiments, the apparatus further comprises a decodingmodule configured to jointly decode the downlink signal and theinterfering signal based on the interfering signal characteristicsinformation.

In various embodiments, the interfering signal characteristicsinformation comprises DCI associated with the interfering signal.

In various embodiments, wherein the communication module is furtherconfigured to receive interfering signal characteristics information byreceiving a Radio Network Temporary Identifier (RNTI) corresponding toan apparatus of an interfering cell and monitoring a control channelsearch space for the DCI based on the received RNTI.

In various embodiments, the RNTI is associated with a second apparatus,the second apparatus associated with the interfering signal.

In various embodiments, the communication module is further configuredto receive a cell ID associated with a neighbouring cell and to monitora control channel associated with the neighbouring cell.

In various embodiments, the apparatus and the second apparatus areassociated with the same control channel search space and are associatedwith a common cell ID; and wherein the size of the DCI contents receivedby each apparatus are the same.

In various embodiments, the RNTI comprises an Interference-AssistanceRNTI (IA-RNTI) associated with a control channel search space dedicatedto interference information.

In various embodiments, the downlink signal comprises a PhysicalDownlink Shared Channel (PDSCH) associated with the apparatus and theinterfering signal comprises a second PDSCH associated with a secondapparatus.

In various embodiments, an apparatus is provided for use in a wirelesscommunication system, the apparatus comprising means for receivinginterfering signal characteristics information, means for receiving adownlink signal in the presence of an interfering signal, and means forsuppressing interference in the received downlink signal caused by theinterfering signal based on the interfering signal characteristicsinformation.

In various embodiments, the apparatus may comprise a system on a chip, achipset, and/or a user equipment. According to various embodiments, theuser equipment may further comprise one or more of: a screen, a speaker,a touchscreen, a keyboard, an antenna array including a plurality ofantennas, a graphics processor, or an application processor. One theskilled in the art understands that a “processing circuitry configuredto” perform a function comprises at least one of “hardware configuredto”, “software configured to” and a “combination of hardware andsoftware configured to” perform that function.

In various embodiments, a method of mitigating interference at a userequipment in a wireless communication system, the method comprisingreceiving, at the user equipment, a physical downlink shared channel(PDSCH) in the presence of an interfering signal, obtaining, at the userequipment, information defining characteristics of the interferingsignal, and suppressing interference caused by the interfering signalwhen receiving the (PDSCH) based on the information definingcharacteristics of the interfering signal.

In various embodiments, the information defining characteristics of theinterfering signal comprises at least one of: a modulation format, apresence and characteristics of interference, a transmission scheme, oneor more reference symbols of the interfering signal, and a modulation orcoding scheme of the interfering signal.

In various embodiments, wherein obtaining information definingcharacteristics of the interfering signal comprises receivinginterfering signal characteristics information transmitted by an evolvednodeB (eNodeB).

In various embodiments, obtaining information defining characteristicsof the interfering signal further comprises receiving Downlink ControlInformation (DCI) associated with the user equipment and comprising aninterference resource block assignment. In various embodiments,receiving the PDSCH further comprises performing joint decoding of thedownlink signal and interfering signal based on the interfering signalcharacteristics information.

In various embodiments, obtaining information defining characteristicsof the interfering signal comprises receiving, at the user equipment,Downlink Control Information (DCI) associated with the interferingsignal.

In various embodiments, wherein receiving the DCI associated with theinterfering signal comprises receiving a Radio Network TemporaryIdentifier (RNTI) corresponding to user equipment of interfering cellsand monitoring a control channel search space for the DCI based on thereceived RNTI.

In various embodiments, receiving DCI information associated with theinterfering signal further comprises receiving a cell ID associated witha neighbouring cell and monitoring a control channel associated with theneighbouring cell.

In various embodiments, a non-transitory computer readable medium isprovided comprising computer program instructions that, when executed onprocessor, cause a user equipment to receive, at the user equipment,interfering signal characteristics information, receive, at the userequipment, a downlink signal in the presence of an interfering signal,and suppress interference in the received downlink signal caused by theinterfering signal based on the interfering signal characteristicsinformation.

In various embodiments, an circuit for use in an eNodeB in a wirelesscommunication system is provided, the circuit comprising a communicationmodule configured to transmit a first downlink signal to a first userequipment an interference management module coupled to the communicationmodule and configured to identify downlink signals in the wirelesscommunication system that are expected to interfere with the firstdownlink signal transmitted to the first user equipment and wherein thecommunication module is further configured to transmit to the first userequipment interfering signal characteristics information relating to anydownlink signals that are identified by the interference managementmodule to be expected to interfere with the downlink signal to the firstuser equipment.

According to various embodiments there is provided a method of providinginterference mitigation information to a UE in a wireless communicationsystem, the method comprising transmitting a first downlink signal to afirst user equipment identifying other signals in the wirelesscommunication system that are expected to interfere with the firstdownlink signal transmitted to the first user equipment, andtransmitting to the first user equipment interfering signalcharacteristics information relating to any signals that are identifiedto be expected to interfere with the first downlink signal.

According to various embodiments, there is provided a non-transientcomputer readable medium comprising computer program instructions thatwhen executed on a processor cause the method of any above describedembodiments to be performed.

The invention claimed is:
 1. A method of mitigating interference at auser equipment in a wireless communication system, the methodcomprising: receiving, at the user equipment, a physical downlink sharedchannel (PDSCH) in the presence of an interfering signal; receiving, atthe user equipment from a serving eNodeB, Downlink Control Information(DCI) to provide information defining characteristics of the interferingsignal; and suppressing interference caused to the PDSCH by theinterfering signal based on the information defining characteristics ofthe interfering signal.
 2. The method of claim 1, wherein informationdefining characteristics of the interfering signal comprises amodulation format, a presence and characteristics of interference, atransmission scheme, one or more reference symbols of the interferingsignal, or a modulation or coding scheme of the interfering signal. 3.The method of claim 1, wherein the DCI comprises an interferenceresource block assignment.
 4. The method of claim 1, wherein the DCI isDCI format 2C.
 5. An apparatus for use in a wireless communicationsystem, the apparatus comprising: communication circuitry to: receive,from a serving eNodeB in Downlink Control Information (DCI), interferingsignal characteristics information; and receive a physical downlinkshared channel (PDSCH) in the presence of an interfering signal; andinterference mitigation circuitry coupled to the communicationcircuitry, the interference mitigation circuitry to suppressinterference caused to the PDSCH by the interfering signal based on theinterfering signal characteristics information.
 6. The apparatus ofclaim 5, wherein the interfering signal characteristics informationcomprises a modulation format, a presence and characteristics ofinterference, a transmission scheme, one or more reference symbols ofthe interfering signal, or a modulation or coding scheme of theinterfering signal.
 7. The apparatus of claim 5, wherein the DCIincludes an interference resource block assignment.
 8. The apparatus ofclaim 7, wherein the interference resource block assignment indicatesone or more physical resource blocks (PRBs) associated with theinterfering signal.
 9. The apparatus of claim 5, wherein the interferingsignal characteristics information comprises demodulation referencesignal (DM-RS) parameters associated with the interfering signal. 10.The apparatus of claim 5, further comprising decoding circuitry tojointly decode the PDSCH and the interfering signal based on theinterfering signal characteristics information.
 11. The apparatus ofclaim 5, wherein the DCI is DCI format 2C.
 12. The apparatus of claim11, wherein the communication circuitry is to receive interfering signalcharacteristics information by receiving a Radio Network TemporaryIdentifier (RNTI) and monitoring a control channel search space for theDCI based on the received RNTI.
 13. The apparatus of claim 12, whereinthe RNTI is associated with a second apparatus, the second apparatusassociated with the interfering signal.
 14. The apparatus of claim 11,wherein the communication circuitry is to receive a cell ID associatedwith a neighbouring cell and to monitor a control channel associatedwith the neighbouring cell.
 15. The apparatus of claim 11, wherein auser equipment and a second user equipment are associated with a samecontrol channel search space and are associated with a common cell ID;and wherein a size of DCI contents received by each apparatus are thesame.
 16. The apparatus of claim 12, wherein the RNTI comprises anInterference-Assistance RNTI (IA-RNTI) associated with a control channelsearch space dedicated to interference information.
 17. The apparatus ofclaim 5, wherein the PDSCH is a first PDSCH and the interfering signalcomprises a second PDSCH associated with a second apparatus.
 18. Acircuit for use in an eNodeB in a wireless communication system, thecircuit comprising: communication circuitry to transmit a first physicaldownlink shared channel (PDSCH) to a first user equipment; interferencemanagement circuitry coupled to the communication circuitry, theinterference management circuitry to identify downlink signals in thewireless communication system that are expected to interfere with thePDSCH transmitted to the first user equipment; and wherein thecommunication circuitry is further to transmit to the first userequipment Downlink Control Information (DCI) including interferingsignal characteristics information relating to any downlink signals thatare identified by the interference management circuitry to be expectedto interfere with the PDSCH to the first user equipment.
 19. The circuitof claim 18, wherein the interfering signal characteristics informationcomprises a modulation format, a presence and characteristics ofinterference, a transmission scheme, one or more reference symbols ofthe interfering signal, or a modulation or coding scheme of theinterfering signal.
 20. One or more non-transient computer readablemedia comprising computer program instructions that when executedimplement a method comprising: receiving, at a user equipment, aphysical downlink shared channel (PDSCH) in the presence of aninterfering signal; receiving, at the user equipment from a servingeNodeB, Downlink Control Information (DCI) to provide informationdefining characteristics of the interfering signal; and suppressinginterference caused to the PDSCH by the interfering signal based on theinformation defining characteristics of the interfering signal.
 21. Theone or more non-transient computer readable media of claim 20, whereininformation defining characteristics of the interfering signal comprisesa modulation format, a presence and characteristics of interference, atransmission scheme, one or more reference symbols of the interferingsignal, or a modulation or coding scheme of the interfering signal. 22.The one or more non-transient computer readable media of claim 20,wherein the DCI comprises an interference resource block assignment. 23.The one or more non-transient computer readable media of claim 20,wherein the DCI is DCI format 2C.